WASHINGTON — Beto O’Rourke announced on Thursday that he is running for president in 2020, saying that the “challenges we face are the greatest in living memory.”

He and his wife posted a video to launch the campaign.

O’Rourke will sit down with CBS News’ Gayle King on Thursday in Burlington, Iowa, for an interview that will air on “CBS This Morning” on Friday. Portions will air on “CBS Evening News” and other network platforms on Thursday evening.

“At this moment of truth — at this moment where we could make or break our democracy, where we will decide the fate of generations to come on this planet — we must all ask what each of us can give to this country and to the people who will inherit the consequences of our choices,” he said in an email to supporters.

O’Rourke broke the news to El Paso TV station KTSM-TV on Wednesday that he had decided to seek the Democratic nomination. He confirmed his plans in a text message to the station.

“I’m really proud of what El Paso did and what El Paso represents,” O’Rourke said in the text to KTSM. “It’s a big part of why I’m running. This city is the best example of this country at its best.”

He will officially kick off his campaign in El Paso on March 30.

O’Rourke came close to defeating Ted Cruz in last year’s Senate race. O’Rourke was a relatively low-key congressman from an El Paso-area district, but his Senate campaign gained traction for its ability to raise huge sums from the grassroots and the candidate’s charisma, which included extensive, verite-like use of Facebook Live.

“I saw firsthand how the purpose and function that we all crave can be found in serving others and serving this country,” he wrote to his supporters.

His presidential announcement video aimed at countering the negative tone of the Trump years with an Obama-like optimistic vision that captivated Democratic primary voters in 2008.

O’Rourke is featured on the cover of Vanity Fair’s April issue, giving him a publicity boost amid a crowded field. More than a dozen Democrats are seeking the nomination, and a few more are expected to enter the race. He’s also the subject of the documentary “Running with Beto,” which debuted at South by Southwest last weekend and will premiere on HBO on May 28.

The Vanity Fair profile, written by Joe Hagan, describes him as “quintessentially Generation X, weaned on ‘Star Wars’ and punk rock and priding himself on authenticity over showmanship and a healthy skepticism of the mainstream.” O’Rourke compared his bid to “every epic movie that you’ve ever seen, from ‘Star Wars’ to ‘The Lord of the Rings.’ This is the moment where we’re going to win or lose everything.”

O’Rourke made his first campaign appearance on Thursday in Keokuk, Iowa, where he told a crowd gathered in a coffee shop that he intended to run a positive campaign.

“Any single Democrat running today would be far better than the current occupant of the White House,” he said.

He talked of the need for universal health care, child care and a $15-per-hour minimum wage, as well as the urgency of broadband access in rural America.

O’Rourke enters the race with the presumed ability to raise huge sums online from small donors, as he did during his Senate run. He also drew heavy interest from showbiz figures during the race and endorsements from figures such as Willie Nelson and Beyoncé, as well as Ellen DeGeneres, who invited him on her show.

He said that he would not be taking money from lobbyists, PACs or corporations. “We will fund this effort without help from any special interests so that we can be sure our democracy is once again powered by people, and only people,” he said.

During his Senate campaign, he did visit Los Angeles to raise money from the large base of progressive donors in showbiz and other professions. In July, he attended a reception at the home of actress Nancy Stephens and director-producer Rick Rosenthal, with co-hosts including location service owner Marilyn Bitner, producer Cotty Chubb, and attorney Tom Hoberman and his wife Ellen, a philanthropist.

The Republican National Committee quickly pounced on O’Rourke’s announcement and called him a “nightmare for America” in a video posted on its Twitter page. It also focuses on O’Rourke’s drunk driving arrest in 1998 when he lost control of his vehicle and hit a truck. A witness said that he tried to flee the scene, but O’Rourke has denied that.

President Trump said of O’Rourke, “I think he’s got a lot of hand movement. I’ve never seen so much hand movement. Is he crazy or is that just the way he acts?”

“Whoever it is I will take him or her on,” he said.